In the May 11 & 25 SN: High-tech cricket farming, AI learns from Minecraft, looking for lithium, a new hominid species is named, signs of life in dead pig brains, Cherokee cave texts decoded, water molecules on the moon and more.

A basketball-sized rock hit the moon during the last lunar eclipse

Professional and amateur astronomers used images and video to analyze the impact

LUCKY STRIKE Amateur astronomers caught lucky views of an object roughly the size of a basketball smacking into the moon and producing a bright flash of light (inset) during a lunar eclipse on January 21.

Thousands of people were watching the total lunar eclipse on January 21 when something suddenly smacked into the moon, creating a flash of light. Now professional and amateur astronomers have used fortuitous photographs of the strike to estimate the object’s size.

Astronomer Jorge Zuluaga and his colleagues gathered images taken by amateurs in Colombia and the Dominican Republic, plus a video that was livestreamed on TimeAndDate.com from an observatory in Morocco, and calculated that the impact probably released the equivalent of about half a ton of TNT in energy.

Zuluaga, of the University of Antioquia in Medellín, Colombia, missed the eclipse due to clouds. But the next day, he saw reports on Twitter that some observers had seen a bright flash, widely interpreted as a meteorite strike. He contacted amateur astronomers he had worked with before, and found that several had caught the impact on camera.

Using those observations, Zuluaga and his team estimated that the impact probably left a crater between 5 and 10 meters wide. That scar could be spotted with a current or future lunar orbiter.

The fact that this impact happened during a lunar eclipse supports the idea that the moon is hit with meteorites almost constantly, Zuluaga says. If such strikes were rare, spotting one during an hour-long total eclipse would be too much of a coincidence. Previous estimates suggest that such objects hit the moon once every hour, on average.

The event also highlights the potential for discovery when amateur and professional astronomers work together. “A lunar eclipse is not as interesting for professionals as for amateur astronomers,” Zuluaga says. “But when you have these kinds of surprises, it is a blessing to have amateurs as friends.”